• Initially, human MVD infection results from prolonged exposure to mines or caves inhabited by Rousettus fruit bat colonies.
• Once introduced in the human population, Marburg virus can spread through human-to-human transmission via direct contact (through broken skin or mucous membranes) with the blood, secretions, organs or other bodily fluids of infected people, and with surfaces and materials (e.g. bedding, clothing) contaminated with these fluids.
• Healthcare workers have frequently been infected while treating patients with suspected or confirmed MVD. This has occurred through close contact with patients when infection control precautions are not strictly practiced. Transmission via contaminated injection equipment or through needle-stick injuries is associated with more severe disease, rapid deterioration, and possibly a higher fatality rate.
• Burial ceremonies that involve direct contact with the body of the deceased can also contribute to the transmission of Marburg virus.
• People cannot transmit the disease before they have symptoms and remain infectious as long as their blood contains the virus.

• The incubation period (interval from infection to onset of symptoms) varies from 2 to 21 days.

• MVD begins abruptly, with high fever, severe headache and severe malaise. Muscle aches and pains are a common feature. Severe watery diarrhoea, abdominal pain and cramping, nausea and vomiting can begin on the third day. Non-itchy rash have been reported in patients between 2 and 7 days after onset of symptoms.

• From day 5 of the disease, patients may develop haemorrhagic manifestations, including fresh blood in vomitus and faeces, and bleeding from the nose, gums and vagina. Bleeding at venepuncture sites (where intravenous access is obtained to give fluids or obtain blood samples) can also be observed. Involvement of the central nervous system can result in confusion, irritability and aggression. Orchitis (inflammation of one or both testicles) has been reported occasionally in the late phase of disease.

• In fatal cases, death occurs most often between 8 and 9 days after symptom onset, usually preceded by severe blood loss and shock.

It can be difficult to clinically distinguish MVD from other infectious diseases such as malaria, typhoid fever, shigellosis, meningitis and other viral haemorrhagic fevers. Confirmation that symptoms are caused by Marburg virus infection are made using the following diagnostic methods:

• antibody-capture enzyme-linked immunosorbent assay (ELISA)
• antigen-capture detection tests
• reverse transcriptase polymerase chain reaction (RT-PCR) assay
• virus isolation by cell culture in maximum containment laboratories.

Samples collected from patients are an extreme biohazard risk; laboratory testing on non-inactivated samples should be conducted under maximum biological containment conditions. All non-inactivated biological specimens should be packaged using the triple packaging system when transported nationally and internationally.

• Early intensive supportive care including rehydration and treatment of specific symptoms, can improve survival.

• Currently there are no vaccines or antiviral treatments approved for MVD.–

• There are candidate monoclonal antibodies (mAbs) and antivirals, along with candidate vaccines that can be evaluated in [clinical trials](https://www.who.int/teams/blueprint/ebolavirus.

• Rousettus aegyptiacus bats are considered natural hosts for Marburg virus. There is no apparent disease in these fruit bats. As a result, the geographic distribution of Marburg virus may overlap with the range of Rousettus bats.

• African green monkeys (Cercopithecus aethiops) imported from Uganda were the source of infection for humans during the first MVD outbreak.

• Experimental inoculations in pigs with different Orthoebolavirus species indicated that pigs are susceptible to filovirus infection and shed the virus. Therefore, pigs should be considered as a potential amplifier host during MVD outbreaks. Precautionary measures are needed in pig farms in Africa to avoid pigs becoming infected through contact with fruit bats.

Community engagement is key to successfully controlling any outbreaks. Outbreak control relies on using a range of interventions, such as case management, surveillance and contact tracing, good laboratory service, infection prevention and control in health facilities, safe and dignified burials and social mobilization.

Raising awareness of risk factors for MVD and protective measures that individuals can take is an effective way to reduce human transmission.

Risk reduction messaging should focus on several factors:

• Reducing the risk of bat-to-human transmission arising from prolonged exposure to mines or caves inhabited by fruit bat colonies. People with visiting or working in in mines or caves inhabited by fruit bat colonies, people should wear gloves and other appropriate protective clothing (including masks). During outbreaks all animal products (blood and meat) should be thoroughly cooked before consumption.
• Reducing the risk of human-to-human transmission in the community arising from direct or close contact with infected patients, particularly with their body fluids. Close physical contact with MVD patients should be avoided. Patients suspected or confirmed for MVD should be isolated in a designated treatment centre for early care and to avoid transmission at home.
• Communities affected by MVD should make efforts to ensure that the population is well informed, both about the nature of the disease itself and about necessary outbreak containment measures.
• Outbreak containment measures include safe and dignified burial of the deceased, identifying people who may have been in contact with someone infected with MVD and monitoring their health for 21 days, separating the healthy from the sick to prevent further spread and providing care to confirmed patient and maintaining good hygiene and a clean environment need to be observed.

• Healthcare workers should always take standard precautions when caring for patients, regardless of their presumed diagnosis. These include basic hand hygiene, respiratory hygiene, use of personal protective equipment (to block splashes or other contact with infected materials), safe injection practices and safe and dignified burial practices.

• Healthcare workers caring for patients with suspected or confirmed MVD should apply extra infection control measures to prevent contact with the patient’s blood and body fluids and contaminated surfaces or materials such as clothing and bedding.

• Laboratory workers are also at risk. Samples taken from humans and animals for investigation of Marburg virus infection should be handled by trained staff and processed in suitably equipped laboratories.